Historically, libraries have divided books into two broad categories; fiction and non-fiction. Examples of fiction are stories, fables and fantasies. The rest is non-fiction, widely considered as fact.
Merriam-Webster defines it as:
"writing that is about facts or real events: all writing that is not fiction."
The digital world has inherited that default definition for non-fiction and is suffering for it.
The first of many problems is that the fiction or non-fiction classification is bestowed by the author. A written piece about traveling to the moon in a basket carried by geese could be speculative non-fiction on alternative methods of spaceflight or a fictional fairy-tale. There is no objective measure which way it is classified. As a result, there are non-fiction writings about how the Holocaust did not happen, genetic superiority or how the government is controlling people through microwave towers, among various other nonsense.
If people just laughed, and some do, that would be fine. However, the ignorant and manipulative people point out that these writings are non-fiction, therefore true and irrefutable. By the assumption of truth and delegation to the category of non-fiction, these falsehoods become defictionalized. They are now free to permeate reality and distort politics, history, science and society.
We need to abandon the old classifications for written material. The writer's desire to portray their work as fiction or non-fiction is irrelevant. What is important is understanding what is true or speculation; what stands up to examination and what is intentional distortion.
Literature and journalistic classification that categorizes writing, imply no degree of validity would be a start. A letter classification (1) Subject (2) Postulation (3) Position. Historic (H) Opinion (O) Critical (C) for example. It would then be up to the writer to support and defend what they espouse rather than simply assigning an implication of truth.
Free speech is not about saying anything without being criticized or not having to defend a position. Free speech is about debate, discourse; embracing good ideas and rejection of flawed, malicious or bad ideas.
David Duke, David Irving, Willis Carto, William Piece, Ben Klassen, Ernst Zundel and George Rockwell for example have all written works of malicious fiction which are classified and tragically accepted as non-fiction.
If we want to avoid drowning in the noise of presumed and unsupported alleged facts, then something must be done.